:root{color-scheme:dark;--bg:#07111f;--panel:#0e1a2a;--soft:#142338;--text:#f5f7fb;--muted:#9fb0c5;--accent:#f5c76f;--line:#26384f;--ok:#70d6a4}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);font:15px/1.55 system-ui,sans-serif}main.shell{width:min(1120px,calc(100% - 32px));margin:auto}.lesson-head{padding:28px 0 18px}.lesson-head a{color:var(--muted);text-decoration:none}.lesson-head h1{max-width:820px;margin:12px 0 8px;font-size:clamp(2rem,5vw,3.6rem);line-height:1.02}.lesson-head p{max-width:760px;color:var(--muted)}.lab{display:grid;grid-template-columns:minmax(0,1.2fr) minmax(300px,.8fr);gap:14px;align-items:start}.panel{border:1px solid var(--line);border-radius:16px;background:var(--panel);padding:16px}.sky{position:relative;min-height:390px;overflow:hidden;background:linear-gradient(#07101e,#16243a 65%,#26354a);border-radius:12px}.stars{position:absolute;inset:0;background-image:radial-gradient(#fff 1px,transparent 1px);background-size:37px 41px;opacity:.55;filter:brightness(var(--scene-brightness,1))}.sky:after{content:"";position:absolute;inset:0;pointer-events:none;opacity:var(--noise-opacity,.08);background-image:repeating-radial-gradient(circle at 20% 30%,rgba(255,255,255,.22) 0 1px,transparent 1px 4px);background-size:7px 9px;mix-blend-mode:screen}.trail{position:absolute;left:50%;top:50%;width:58%;height:58%;border:2px solid color-mix(in srgb,var(--accent) 72%,transparent);border-left-color:transparent;border-bottom-color:transparent;border-radius:50%;transform:translate(-50%,-50%) rotate(-20deg);opacity:.25}.scene-copy{position:absolute;left:18px;right:18px;bottom:18px;padding:12px;border-radius:12px;background:rgba(3,8,14,.72);backdrop-filter:blur(10px)}.scene-copy strong{font-size:1.15rem}.scene-copy span{display:block;color:#c4d0df;font-size:.78rem;margin-top:3px}.controls{display:grid;gap:14px}.control label{display:flex;justify-content:space-between;gap:12px;font-weight:700}.control small{color:var(--muted)}input[type=range]{width:100%;margin-top:8px;accent-color:var(--accent)}.metrics{display:grid;grid-template-columns:1fr 1fr;gap:8px}.metric{padding:11px;border-radius:11px;background:var(--soft)}.metric small{display:block;color:var(--muted);font-size:.68rem}.metric strong{display:block;margin-top:4px;font-size:1.05rem}.decision{margin-top:12px;padding:12px;border-left:3px solid var(--accent);background:var(--soft);border-radius:0 10px 10px 0}.decision b{color:var(--accent)}.sensor-aware{display:grid;gap:10px;padding-top:14px;border-top:1px solid var(--line)}.sensor-aware-head strong{display:block;font-size:.82rem}.sensor-aware-head small{display:block;margin-top:3px;color:var(--muted);font-size:.66rem;line-height:1.45}.sensor-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px}.sensor-grid .full{grid-column:1/-1}.sensor-aware .control label{font-size:.72rem}.pixel-drift{border:1px solid color-mix(in srgb,var(--accent) 22%,var(--line));background:color-mix(in srgb,var(--accent) 6%,var(--soft))}.pixel-drift strong{font-variant-numeric:tabular-nums}.lesson-flow{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin:14px 0 30px}.lesson-flow section{border:1px solid var(--line);border-radius:14px;padding:14px;background:var(--panel)}.lesson-flow h2{font-size:.9rem;margin:0 0 6px}.lesson-flow p,.lesson-flow li{color:var(--muted);font-size:.76rem}.lesson-flow ul{padding-left:18px;margin:6px 0}.links{display:flex;gap:8px;flex-wrap:wrap}.links a{padding:9px 12px;border:1px solid var(--line);border-radius:999px;color:var(--text);text-decoration:none;font-size:.75rem}.fact{color:var(--ok)!important}.approx{color:var(--accent)!important}@media(max-width:760px){main.shell{width:min(100% - 18px,1120px)}.lesson-head{padding-top:18px}.lab{grid-template-columns:1fr}.sky{min-height:300px}.lesson-flow{grid-template-columns:1fr}.metrics{grid-template-columns:1fr 1fr}.panel{padding:11px}}@media(max-width:430px){.sensor-grid{grid-template-columns:1fr}.sensor-grid .full{grid-column:auto}}@media(max-width:390px){.sky{min-height:270px}.metrics{grid-template-columns:1fr}.lesson-head h1{font-size:1.85rem}}
/* parameter-visual-contract */
.sky{filter:brightness(var(--scene-exposure,1));transition:filter .16s}.stars{background-image:radial-gradient(#fff var(--star-size,1px),transparent calc(var(--star-size,1px) + .45px));transform-origin:center;transition:transform .16s,filter .16s}.trail{transition:opacity .16s,transform .16s,border-width .16s}.sky[data-high-iso='1']:after{mix-blend-mode:screen}

.course-overview-image{margin:14px 0 22px;width:min(100%,560px);border:1px solid var(--border);border-radius:16px;overflow:hidden;background:var(--surface)}.course-overview-image img{display:block;width:100%;height:auto;aspect-ratio:14/9;object-fit:cover}.course-overview-image figcaption{padding:9px 12px;color:var(--muted);font-size:.72rem;line-height:1.45}


/* WTS lesson split alignment v1 — 2026-09-23 */
@media(min-width:1024px){.lab{grid-template-columns:minmax(0,1.45fr) minmax(340px,.72fr);gap:22px;align-items:start}.lab>*{min-width:0;align-self:start}.controls{gap:16px}.metrics,.sensor-grid{gap:10px}.metrics{grid-auto-rows:1fr}.lesson-flow{gap:14px;grid-auto-rows:1fr}.lesson-flow>*{height:100%}}